Motor fuels



Patented Nov. 7, 1950 MOTOR FUELS William Arthur Partridge and Harold John Alty,

sunburyn-T m England,

assignors to Anglo-Iranian Oil Company Limited, London, England, a British joint-stock corporation No Drawing. Application September 20, 1946,

Serial No. 698,406. In Great Britain September 21, 1945 4 Claims.

The invention relates to the stabilisation of motor and aviation fuels containing anti-knock reagents.

The use of anti-knock reagents containing tetra-ethyl lead is widely known in the preparation of high quality fuels for use in internal combustion engines. In recent years there has been a growing demand for fuels showing a still greater resistance to knock, and particularly for aviation fuels. .With a view to facilitate production of such fuels ofiicial specifications have appreciably relaxed the lead tolerance, and the inclusion in such fuels of much larger proportions of antiknock reagents is now permitted.

It is known that gasoline containing tetraethyl lead, and particularly aviation gasolines, which normally contain a higher proportion of the anti-knock reagent than motor gasolines, are liable to become unstable in storage, and to deposit a white precipitate containing lead. This instability becomes more marked as the lead content of the fuel rises, and thus the relaxation in lead tolerance allowed by oflicial specifications accentuates the instability of such leaded fuels.

We have found that elemental sulphur, hy-

- drogen sulphide, carbon disulphide, thiophene and dialkyl disulphides have a marked effect in producing instability, and that instability also appears to be promoted by certain olefins. Alkyl sulphides (thioethers) and mercaptans do not however appear to have any appreciable effect on the stability of a leaded fuel.

According to the invention, motor and aviation fuels containing tetra-ethyl lad are stabilised by the addition thereto of a minor proportion of a monocarboxylic acid or a salt or derivative thereof, but not including an ester thereof.

According to the invention moreover, monobasic fatty acids, or salts or derivaties of monobasic fatty acids, with the exception of esters, are employed as the inhibitors and in particular lead acetate, ammonium acetate and acetamide. Other mono-carboxylic acids, their salts and derivatives, with the exception of esters, may be used, however, whereas dibasic and hydroxy acids have no inhibiting properties.

The amount of the inhibitor required does not substantially exceed 0.01% by weight of the fuel, and in many cases satisfactory results are achieved when the fuel contains as little as 0.001% of the inhibitor.

The inhibitor may be incorporated in the fuel in a number of ways. It may be added for example to the finished fuel, or to any constituent of the fuel prior to blending, or to the antiknock reagent, or it may be incorporated in the blending process or in the leading operation.

Lead salts are generally only sparingly soluble in motor and aviation fuels, and in order effectually to incorporate such salts of very low solubility in the fuel an excess of the salt may be added to' the fuel, the exceedingly dilute solution formed being decanted. 0r again the lead salt, and particularly lead acetate. may for example be added in the form of an alcoholic solution,

- since an apparent increase in the solubility of the salt in the fuel is thereby attained.

The following four non-inhibited fuels, each containin 5.5 ML'I'EL/IG, were subjected to storage tests carried out in the dark at a temperature of 120 F. Fuel A was a commercial aviation fuel; fuel B was a sulphur-free isooctane to which thiophene had been added in quantity sufficient to give the fuel a sulphur content of .005% by weight; fuel C was a sulphurfree iso-octane to which carbon disulphide had been added in quantity suflicient to give the fuel a sulphur content of .005% by weight; fuel D was a commercial aviation spirit.

The days required for the formation of precipitate with the non-inhibited fuels referred to were found to be as follows:

' Fuel Trace Medium Heavy A l 2 B 5 6 8 C 1 52 D l.

3 4 addsotherthlnfattymandthelneleetlve- .l'mple: ms of organic acids other than monoearboaylic n rum adds. m

[sample 1 a Trade India- Heavy Days hm medalists in Pmshldmmhlnhiflfln Mm. momma-11mm a m daioted y the m m 1 1s MA'B'OMD 'll'lee m Heavy mmminmzetaten 7 l 1. a 396mm 2 1mm Fuel (Ha-mud with lead pllmi- 7 a-pmzmuudd 1e s n-1m AW Example 4 15 n+.m1 aeefleanhydrido a a as g No Mum m1 oeetieanhydflde z: 41 4 cimzmmm mm 1,,

m lledium Heavy mm; m... 1s 40 3+4! aeetamide" 10 as 6 +m 14 I xfmnwfi 7 Bled uIAm-onia. FM m m mum I V m 1 2 a+.oo1% ammonium 11 13 11:1 B+0.ml%anun1mimn bmsoato. 1 10 .0011, hrmlonnate 14 1o fim u 2... meme 2393: 2 a spa qfAn-nia- Add: ALL :P 1 5 Fuel C+0ml% ammmium benmaie n ammonium mu... 9 1: a4 l se mm m- :2 2 2: -6 1 1 Bi 00m MIL: is 34 85 m 1 z M0195 ammmmm aoetate 34 I 49 3 .mmm m 21 an 85 O-I-.Ml%ammminmaeehte----...- 0 34 49 w l i d mw 1. Astabilisedgasolineforuseinintenmlcomm 7 H m bustion engims, said gasoline containing tetra- B-rexmszincaeehte. 1 11 m as ethyl lead as anti-knock reagent and a small g 6 g amount of an agent for preventing the formation B-Mleadaeehte 22 25 as of lead-containing precipitate, said agent being h-m u uigw I g a compound of the formula CHaCOR, where R a isaradicalselectedfromthegroupconsistingof El IIAIWII n 0 OH, OCOCHa, N112, and ONa. A+.llll%unmoninm butynte- 1s 21 2. A stabilised gasoline for use in internal comg l m {3 hustion engines, said gasoline containing tetrac+ ethyl lead ,as anti-hiockreagent and a small WM amount of an agent for preventing the formation 1 4 of lead-containing precipitate, said agent being 8 9 a compound of the formula. CHaCOR, where R EIedqfA-Iom'a- Swdeis a radical selected from the group consisting of 0E0COCH3,NHz,andONaandthesmal1 m 1 1 mmm 8 u 4 amount of the stabilising agent does not substantially exceed 0.01% by weight of the gasoline, and is not substantially less than 0.001%. 31 m I I :3 3. The method of stabilising gasoline for we in internal combustion engines, said gasoline con- Empu 2 taining tetraethyl lead as anti-knock reagent, 5 which comprises mixing a small amount of an Dayswmm min 5 agent for preventing the formation of lead-com- Pmmm-m d m s I me taining precipitate with the gasoline. said agent added as inhibitor s r: umbqmn being a compound of the formula CHaCOR. where Tm Mm Risaradical selected from the group consisting of OH, OCOCHJ, NH:. and ONa. aim my] 6 7 1o 4. The method of stabilising gasoline for use 0+ 001% methyl 2 3 in internal combustion engines, said gasoline 53%;; 52 l g containing tetraethyl lead as anti-knock reagent, O+.om%1-:1hy1m1-1- g which comprises mixing a small ammmt of an Ij$$fi 2 #7 m agent for preventing the formation of lead-con- G+.06% y i g taining precipitate with the gasoline, said agent j gifififi}; 5 5 10 being a compound of the formula CHaCOR, where grams my! f R is a. radical selected from the group consisting 113333, $31; 3 of on. ococm. um. and om, and m which g+m{% pheny} 8 the amount of said agent does not substantially $3,? my] exceed 0.01% by weight of the gasoline, and is g+ggl rg x: 12 not substantially less than 0.001%. AiI$ WZ n, "1 53 2 4 g WILLIAM ARTHUR. PAR'I'RDGE.

1 3 g y! m2 HAROLD JOHN ALTY.

(References on following me) 5 REFERENCES CITED Number The following references are of record in the ,210,942 file of this patent: UNITED STATES PATENTS Number Name Date 5 2,119,240 Lyons Mar. 31, 193:: Number 97,498 Guthmann A 16, 1940 519,855

Name Date Lipkin Aug. 13, 1940 Chenicek Sept. 15, 1942 Cantrell et a1 Sept. 15, 1942 FOREIGN PATENTS Country Date Great Britain Apr. 8, 1940 

1. A STABLISED GASOLINE FOR USE IN INTERNAL COMBUSTION ENGINES, SAID GASOLINE CONTAINING TETRAETHYL LEAD AS ANTI-KNOCK REAGENT AND A SMALL AMOUNT OF AN AGENT FOR PREVENTING THE FORMATION OF LEAD-CONTAINING PRECIPITATE, SAID AGENT BEING A COMPOUND OF THE FORMULA CH3COR, WHERE R IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF OH, OCOCH3, NH2, AND ONA. 